BSD 4.4 Lite bin Sources

1 files changed, 348 insertions, 0 deletions

diff --git a/bin/sh/trap.c b/bin/sh/trap.c
new file mode 100644
index 0000000..dde6dbc
--- /dev/null
+++ b/bin/sh/trap.c
@@ -0,0 +1,348 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+static char sccsid[] = "@(#)trap.c	8.1 (Berkeley) 5/31/93";
+#endif /* not lint */
+
+#include "shell.h"
+#include "main.h"
+#include "nodes.h"	/* for other headers */
+#include "eval.h"
+#include "jobs.h"
+#include "options.h"
+#include "syntax.h"
+#include "signames.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+#include "trap.h"
+#include "mystring.h"
+#include <signal.h>
+
+
+/*
+ * Sigmode records the current value of the signal handlers for the various
+ * modes.  A value of zero means that the current handler is not known.
+ * S_HARD_IGN indicates that the signal was ignored on entry to the shell,
+ */
+
+#define S_DFL 1			/* default signal handling (SIG_DFL) */
+#define S_CATCH 2		/* signal is caught */
+#define S_IGN 3			/* signal is ignored (SIG_IGN) */
+#define S_HARD_IGN 4		/* signal is ignored permenantly */
+#define S_RESET 5		/* temporary - to reset a hard ignored sig */
+
+
+extern char nullstr[1];		/* null string */
+
+char *trap[MAXSIG+1];		/* trap handler commands */
+MKINIT char sigmode[MAXSIG];	/* current value of signal */
+char gotsig[MAXSIG];		/* indicates specified signal received */
+int pendingsigs;			/* indicates some signal received */
+
+/*
+ * The trap builtin.
+ */
+
+trapcmd(argc, argv)  char **argv; {
+	char *action;
+	char **ap;
+	int signo;
+
+	if (argc <= 1) {
+		for (signo = 0 ; signo <= MAXSIG ; signo++) {
+			if (trap[signo] != NULL)
+				out1fmt("%d: %s\n", signo, trap[signo]);
+		}
+		return 0;
+	}
+	ap = argv + 1;
+	if (is_number(*ap))
+		action = NULL;
+	else
+		action = *ap++;
+	while (*ap) {
+		if ((signo = number(*ap)) < 0 || signo > MAXSIG)
+			error("%s: bad trap", *ap);
+		INTOFF;
+		if (action)
+			action = savestr(action);
+		if (trap[signo])
+			ckfree(trap[signo]);
+		trap[signo] = action;
+		if (signo != 0)
+			setsignal(signo);
+		INTON;
+		ap++;
+	}
+	return 0;
+}
+
+
+
+/*
+ * Clear traps on a fork.
+ */
+
+void
+clear_traps() {
+	char **tp;
+
+	for (tp = trap ; tp <= &trap[MAXSIG] ; tp++) {
+		if (*tp && **tp) {	/* trap not NULL or SIG_IGN */
+			INTOFF;
+			ckfree(*tp);
+			*tp = NULL;
+			if (tp != &trap[0])
+				setsignal(tp - trap);
+			INTON;
+		}
+	}
+}
+
+
+
+/*
+ * Set the signal handler for the specified signal.  The routine figures
+ * out what it should be set to.
+ */
+
+int
+setsignal(signo) {
+	int action;
+	sig_t sigact;
+	char *t;
+	extern void onsig();
+	extern sig_t getsigaction();
+
+	if ((t = trap[signo]) == NULL)
+		action = S_DFL;
+	else if (*t != '\0')
+		action = S_CATCH;
+	else
+		action = S_IGN;
+	if (rootshell && action == S_DFL) {
+		switch (signo) {
+		case SIGINT:
+			if (iflag)
+				action = S_CATCH;
+			break;
+		case SIGQUIT:
+#ifdef DEBUG
+			{
+			extern int debug;
+
+			if (debug)
+				break;
+			}
+#endif
+			/* FALLTHROUGH */
+		case SIGTERM:
+			if (iflag)
+				action = S_IGN;
+			break;
+#if JOBS
+		case SIGTSTP:
+		case SIGTTOU:
+			if (mflag)
+				action = S_IGN;
+			break;
+#endif
+		}
+	}
+	t = &sigmode[signo - 1];
+	if (*t == 0) {	
+		/* 
+		 * current setting unknown 
+		 */
+		sigact = getsigaction(signo);
+		if (sigact == SIG_IGN) {
+			if (mflag && (signo == SIGTSTP || 
+			     signo == SIGTTIN || signo == SIGTTOU)) {
+				*t = S_IGN;	/* don't hard ignore these */
+			} else
+				*t = S_HARD_IGN;
+		} else {
+			*t = S_RESET;	/* force to be set */
+		}
+	}
+	if (*t == S_HARD_IGN || *t == action)
+		return 0;
+	switch (action) {
+		case S_DFL:	sigact = SIG_DFL;	break;
+		case S_CATCH:  	sigact = onsig;		break;
+		case S_IGN:	sigact = SIG_IGN;	break;
+	}
+	*t = action;
+	return (int)signal(signo, sigact);
+}
+
+/*
+ * Return the current setting for sig w/o changing it.
+ */
+sig_t
+getsigaction(signo) {
+	struct sigaction sa;
+
+	if (sigaction(signo, (struct sigaction *)0, &sa) == -1)
+		error("Sigaction system call failed");
+
+	return sa.sa_handler;
+}
+
+/*
+ * Ignore a signal.
+ */
+
+void
+ignoresig(signo) {
+	if (sigmode[signo - 1] != S_IGN && sigmode[signo - 1] != S_HARD_IGN) {
+		signal(signo, SIG_IGN);
+	}
+	sigmode[signo - 1] = S_HARD_IGN;
+}
+
+
+#ifdef mkinit
+INCLUDE "signames.h"
+INCLUDE "trap.h"
+
+SHELLPROC {
+	char *sm;
+
+	clear_traps();
+	for (sm = sigmode ; sm < sigmode + MAXSIG ; sm++) {
+		if (*sm == S_IGN)
+			*sm = S_HARD_IGN;
+	}
+}
+#endif
+
+
+
+/*
+ * Signal handler.
+ */
+
+void
+onsig(signo) {
+	signal(signo, onsig);
+	if (signo == SIGINT && trap[SIGINT] == NULL) {
+		onint();
+		return;
+	}
+	gotsig[signo - 1] = 1;
+	pendingsigs++;
+}
+
+
+
+/*
+ * Called to execute a trap.  Perhaps we should avoid entering new trap
+ * handlers while we are executing a trap handler.
+ */
+
+void
+dotrap() {
+	int i;
+	int savestatus;
+
+	for (;;) {
+		for (i = 1 ; ; i++) {
+			if (gotsig[i - 1])
+				break;
+			if (i >= MAXSIG)
+				goto done;
+		}
+		gotsig[i - 1] = 0;
+		savestatus=exitstatus;
+		evalstring(trap[i]);
+		exitstatus=savestatus;
+	}
+done:
+	pendingsigs = 0;
+}
+
+
+
+/*
+ * Controls whether the shell is interactive or not.
+ */
+
+
+void
+setinteractive(on) {
+	static int is_interactive;
+
+	if (on == is_interactive)
+		return;
+	setsignal(SIGINT);
+	setsignal(SIGQUIT);
+	setsignal(SIGTERM);
+	is_interactive = on;
+}
+
+
+
+/*
+ * Called to exit the shell.
+ */
+
+void
+exitshell(status) {
+	struct jmploc loc1, loc2;
+	char *p;
+
+	TRACE(("exitshell(%d) pid=%d\n", status, getpid()));
+	if (setjmp(loc1.loc)) {
+		goto l1;
+	}
+	if (setjmp(loc2.loc)) {
+		goto l2;
+	}
+	handler = &loc1;
+	if ((p = trap[0]) != NULL && *p != '\0') {
+		trap[0] = NULL;
+		evalstring(p);
+	}
+l1:   handler = &loc2;			/* probably unnecessary */
+	flushall();
+#if JOBS
+	setjobctl(0);
+#endif
+l2:   _exit(status);
+}